Alex Lifeson OC (born Alexander Zivojinovich on August 27, 1953, in Fernie, British Columbia, Canada), is a Canadian musician, best known as the guitarist for the rock group, Rush.

Lifeson founded Rush in the summer of 1968, and has been an integral member of the three-piece band ever since. For Rush, Lifeson plays electric and acoustic guitars as well as other stringed instruments such as mandola, mandolin and bouzouki. He also performs backing vocals in live performances, and occasionally plays keyboards and bass pedal synthesizers. During live performances, Lifeson, like the other members of Rush, performs real-time triggering of sampled instruments, concurrently with his guitar playing. The bulk of Lifeson's work in music has been with Rush, although Lifeson has contributed to a body of work outside of the band as well. Aside from music, Lifeson is part owner of the Toronto restaurant The Orbit Room, and is a licensed aircraft pilot, motorcycle rider, and gourmet cook.

Along with his bandmates Geddy Lee and Neil Peart, Lifeson was made an Officer of the Order of Canada on May 9, 1996. The trio was the first rock band to be so honored, as a group.